fix: resolve TypeScript compilation errors from service extraction

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/routes/admin/projects.ts

@@ -67,7 +67,7 @@ export default async function projectsRoutes(fastify: FastifyInstance): Promise<
       userId: authData.userId,
       firstName: authData.firstName,
       lastName: authData.lastName,
-      content: parsed.data.content,
+      content: parsed.data.content ?? undefined,
     });
 
     return success(reply, { note }, 201, 'Poznámka byla přidána');